Photocomposing machines

ABSTRACT

A photocomposing machine having a character drum that is stepped backwards and forwards to bring a group of character images to a photographic position; an optical system images all characters of the group at a common position and a shutter (or equivalent) mechanism selects one character of the group for imaging on a sensitized sheet. A flexible font element having characters arranged thereon in columns and rows is replaceably mounted on the character drum.

United States Patent [191 Grube et a1.

[ June 12, 1973 PHOTOCOMPOSING MACHINES [75] Inventors: Wolfgang OttoGrube, Leonia, N.J.; Joel S. Harris, Valley Stream; Uri Z. Escoli,Forest Hills, both of N.Y.

[73] Assignee: Eltra Corporation, New York, N.Y.

[22] Filed: May 26, 1971 [21] Appl. No.: 146,873

[52] US. Cl. 95/4.5 [51] Int. Cl .1 B4lb 17/12 [58] Field of Search95/4.5

[56] References Cited UNITED STATES PATENTS 2,725,803 12/1955 Tansel95/4 5 2,780,151 2/1957 Borisof 3,074,328 1/1963 Rossetto 3 ,044,3747/1962 Friedman 2,298,666 10/1942 Whitelaw 95/4 5 2,579,287 12/1951Albert 95/100 3,552,285 1/1971 McCall 95/45 FOREIGN PATENTS ORAPPLICATIONS 679,930 9/1952 Great Britain 95/45 398,469 12/1931 GreatBritain 95/4.5

Primary Examiner-John M. Horan Attorney-William P. Keegan [5 7] ABSTRACTA photocomposing machine having a character drum that is steppedbackwards and forwards to bring a group of character images to aphotographic position; an optical system images all characters of thegroup at a common position and a shutter (or equivalent) mechanismselects one character of the group for imaging on a sensitized sheet. Aflexible font element having characters arranged thereon in columns androws is replaceably mounted on the character drum.

8 Claims, 4 Dravving Figures PHOTOCOMPOSING MACHINES The inventionrelates to photocomposing machines and to the character fonts usedthereon.

The prior art is replete with photocomposing machines of variousconfigurations. For example, there are photocomposing machines whichutilize a font plate in the form of a flat disk with character imagesarranged thereon seriatum in a circle. Additional characters may beprovided in the same fashion other circles, concentric with the first.The disk rotates continuously to bring the characters in a circle to aprojection position one after another, and if cahracters from a dfferentcircle of characters are to be photographed the axis of rotation of thedisk is shifted so that the characters in the different circle passthrough the projection position seriatum. The characters selected forcomposition are projected through an optical system to a sensitizedsheet by means of an intermittently operated flash lamp that is actuatedat the instant a selected character is at the projection position. Thesensitized sheet, or preferably some element of the optical system, ismoved interrnittently btween flash lamp actuations to cause successivecharacter images to be projected to unexposed portions of the sensitizedsheet. Another prior art photocomposing machine is similar to theforegoing except that the character front plate is in the form of asquare plate on which the characters are arranged in columns and rows.The font plate is stepped in two directions to bring a selectedcharacter to the photographic or projection position. In another priorart photocomposing machine the character font plate is again a squareplate on which the characters are arranged in columns and rows, but inthis machine, the font plate is stationary during composition of thetext material. Thus instead of moving the font plate to bring a selectedcharacter to the projection position, resort is had to an optical systemthat brings an image of each character on the font plate to a commonposition where it can be recorded on a sensitized sheet. A shuttersystem is included in the latter apparatus so that only one characterimage is projected at a time.

The present invention is intended to provide a simple inexpensivemachine that has the advantages of all the photocomposing machinesreferred to above. Thus the present photocomposing machine will embody afont element on which the characters are arranged in columns and rowsand in which the element will be moved to bring a slected column ofcharacters into a photographic position and an optical scheme will beused to select one of the characters in a column for projection to asensitized sheet. Thus the object of the present invention is to providean improved photocomposing machine.

In carrying out the invention, a character font element in the form of aflexible strip is provided as is a character drum on the circumferenceof which can be mounted a plurality of individually interchangeable fontelements. The drum will be driven by a stepping motor than can bring aselected column of a font element to a photographic position. A seriesof collimating lenslets, one for each character in a column, will bepositioned in front of the character drum, and a shutter mechanism willbe provided so that the light projected through a column of characterson the font element will pass only through the lenslet associated withthe character to be imaged on a sensitized sheet. An optical system willform an image of the selected character on the sheet in a manner laterto be described.

Features and advantages of the invention may be gained from theforegoing and from the dscription of a preferred embodiment thereofwhich follows:

FIG. 1 is a prospective view schematically showing the characterpresentation scheme for the present photocomposing machine;

FIG. 2 is a prospective view of the character font drum;

FIG. 3 is an elevational view of a character font element; and

FIG. 4 is a plan view of the same.

Referring now to the drawing, the present invention will be disclosed insufficient detail to enable its practice by those skilled in the art.The character font drum 10 comprises a transparent ring which is mountedon a disk which in turn is mounted for rotary mounted for rotarymovement in a horizontal plane. The ring is preferably colorlessPlexiglass that is optically clear and free of air bubbles, striae, andinclusions. The disk also is preferably formed of Plexiglass, but it isopaque black. Around the periphery of the drum are located mountingmeans for the character font element. These will later be described indetail with reference to FIG.

2 of the drawing. Internally of the ring is a source of illumination l1and a condenser lens assembly 12 that evenly distributes the light fromsource 11 through the transparent ring and a character font elementmounted thereon. Immediately in front of character drum 10 is anadjustable slit mechanism 13 which controls the width of the light beamemitted from the drum and through a font element. This mechanism 13 isprovided since character font elements having character images ofdifferent point sizes are provided for use in the machine, andconsequently means are needed to limit the width of the band of lighttransmitted to the width of an em square of the point size of thecharacters on the font element in use. A solenid 14 is provided toactuated slit mechanism 13 and widen the spacing between its memberswhen a larger point size font element is in use. Perhaps it will be wellto state now that the character images are arranged on the font elementin columns and rows with a column of characters being brought intoposition behind the shutter mechanism by rotation of the drum. In thecommercial embodiment of the invention, drum 10 is rotated in steps by astepping motor but others might prefer to have it rotate continuously.In either case, the rotating mechanism and its control is generallyknown and need not be described in detail.

Elements now to be described will permit one of the character images ina column to be projected through the remainder of the characterpresentation arrangement. A shutter 16 comprising a plurality ofindividually operated blades, one for each character in a column on thefont element, is provided. The shutter blades are each operated by aseparate rotary solenoid and if its associated solenoid is energized ablade will be rotated out-of the path of the light passing through oneof the character images on the font element. Of course, only a singleblade will be operated at a time. The position of the light which istransmitted when a single shutter blade is actuated forms a singlecharacter and will next pass through a lenslet 15. Again the lenslet isone of a plurality of lenslets provided, one for each character image ina column on the font element. The lenslets are separated from the fontelement by a distant equal to the focal length of the lenslets, hencethe light passing through any lenslet will be collimated or selfparallel light. Consequently when it passes through an imaging lens itwill be refracted to the optical axis of the system. It this way lightpassing through any one of the columnly arranged lenslets will beprojected to a common imaging position on the axis of the imaging lens.Lenslets 15, along with lenses 20, 21, and 22 form a zoom lens assembly17 with lenses 20 and 21 being axially movable to change the effectivefocal length of zoom lens assembly 17. By changing the effective focallength of the zoom lens assembly the point size of the character imagesat the film plane 'can be controlled and the character size of thephototypeset characters thus determined. As the light passes through thezoom assembly, it remains collimated or rather it energes from theassembly as collimated light having been imaged in space within the zoomsystem. The collimated light from the zoom system than enters adecollimator or image forming lens 23. This lens is a multielement lensand it acts to form a real image of the projected character in its focalplane. The light from the lens however is reflected by a mirror 24 to acurved film holder 25 which is located in the focal plane of lens 23.The mirror pivots about a vertical axis and in this manner successiveimages can be placed alongside one another in text composition on filmpositioned in holder 25. The movement of the mirror is controled by astepping motor that steps mirror 24 in variable increments depending onthe widths of the characters being imaged on the film. Mirror 24 isstationary during the interval of flash of light source 11.

The mirror in addition to being positioned to direct the projected lightto the curved film holder 25 as shown, may also be rotated 90 to theposition shown in dotted line in which case the projected light will bedirected to an auxiliary lens 26 and through a pentaprism 27 to a secondfilm plane shown at 30. When the mirror is positioned as shown in thedotted lines and the light from a character on the font element isprojected through lens 26 and prism 27, the mirror will remainstationary during projection of successive character images and thesensitized sheet or film located in the auxiliary film plane will bestepped during the interval between character projections. This latterarrangement is provided to permit setting of large points size type asin headlines and display ads and that is why an additional lens, i.e.,lens 26, is provided to enable the enlargement of the projected imagebeyond the size possible with the basic optical elements of the system.

Attention is now directed to the character drum shown in FIG. 2. Atransparent plastic ring 31 is provided as heretofore explained, and itis secured by an adhesive to a plane disk 32. The disk is formed at itscentral position with a hub, not shown, by which it is connected to adrive mechanism which in the preferred arrangement is a stepping motor.The periphery of the drum is provided with a pair of hook elements 33and 34 respectively located near its upper and lower edges. A furtherpair of pins 35 and 36 are provided in the same segment of the drum asare a pair of sphericallyshaped members 37 and 40. This set of elements,that is, hooks 33 and 34, pins 35 and 36, and members 37 and 40, areprovided for the mounting of a font element on the periphery of thedrum. Similar sets of elements are provided around the circumference ofthe drum; and consequently, a number of font elements can be mounted onthe drum. The function of the various mounting will become clear afterthe font element itself is described. A plurality of indicia 41 aremarked on ring 31 to indicate various font positions on the characterdrum. A slot 42 is provided in the bottom disk 32 of the character drumand it together with a stationary light source and photo-diode device(not shown) enable the drum to be returned to the home position wheneverit is desired to do so.

Reference is now made to FIGS. 3 and 4 for a description of the fontelement. The font element 43 is a photographic negative in which thecharacter images are transparent against an opaque background. Forconvenience, the drawing appears to show the reverse, namely, an opaquecharacter and a transparent background. In the drawing the charactersare represented by rectangles 63 which define the area in which thechracters can be located. In the upper left hand square a particularcharacter, namely, the letter capital F, is shown. Moreover, thecharacter is shown upside down and reversed as it actually would appearon the font element. The optical system reverses the image as it istransmitted through the various optical elements schematically shown inFIG. 1 so that when a projected character is finally imaged on thesensitized sheet or film, it will be correctly oriented. The fontelement itself is provided with a number of apertures. Specifically,apertures 45 and 49 near the leading edge of the element and apertures50 and 51 near its trailing edge. Moreover, an alignment aperture 46precisely located on the font element is provided as is an elongatedslot 47. The aperture 46 and slot 47 are the reference points on thefont element and all character images and timing marks will photographonto the font element with accurate reference thereto. Timing marks,e.g. and 66, are provided for each column of characters formed on fontelement 43 with the right hand edge 67 of each timing slot aligned withthe leading or left hand edge of each rectangle in which a characterimage is positioned. The crosses shown on the character rectangles(which are not really provided on the font elements) of the two leftcolumns in FIG. 2 represent the optical axis of the optical system withrespect to the particular character rectangle and the character imagesare located with respect to this reference point. The font element 43has a plastic reenforcing bar 52 rivetted to it at its leading edge by apair of rivets 53 and 54. A second plastic reenforcng bar 55 is rivettedto the trailing edge of the font element by a pair of rivets 56 and 57.This second bar supports a spring element or a wire spring 60 thattraverses aperture 50 and wire spring 61 which traverses aperture 51. Inmounting a font element 43 on character drum 10, the element is placedover the hooks 33 and 34 such that they pass through apertures 49 and 45and bear against plastic bar 52. The position of the font element isthen adjusted until pin 35 presses through the reference aperture 46which thus locates the font element at a precise position along theperiphery of the character drum. Pin 36 projects through the elongatedslot 47 and thus serves to prevent skewing of the element on the drum10. In other words, the horizontal alignment of font element 43 on thedrum is thereby controlled. The trailing edge of the font element isthen pressed against the surface of drum 10 until the members 37 and 40project through apertures 50 and 51. The springs 60 and 61 snap over thewidest portion of the spherically-shaped ing marks 65, 66 extends belowthe lowest surface of 5 the drum and between a light source andphoto-diode type element (not shown) which are mounted below therotatable character drum. A segment 62 of font element 43 is madetransparent so that when the font element is mounted on drum an indic'ia41 provided on the drum to indicate the font position will be readablewithout the need to remove the font element. Thus in FIG. 2, fontelement 43 is shown as positioned in font position 5.

The operation of a photocomposing machine embodying the presentinvention will be described with reference to the apparatus shown inFIG. 1. It is not believed necessary to describe the control circuitryof the apparatus since the necessary circuit design is well within thecapabilities of those skilled in the art. The photocomposing machinewill be described as though it were operated under control of a codedtape, although it is understood that a keyboard which is an integralpart of the photocomposing machine could also be used. Both arrangementshave' been used many times in the photocomposing machine arts and theirinterchangeability is well understood within this art. The characterdrum will initially be present at a start-of-line or home position asdetermined by the home position slot 42. The mirror 24 will also bepositioned at a startof-line position is determined, for example, by amechanical stop. The coded control tape will be placed in a tape reader,and the firct character code will be coded. The electrical circuitry ofthe system will respond to the code and cause the character drum to stepto a position such that the timing mark for the column of charactersfrom which the character selected is to be photographed and the timingmark next adjacent to its right will straddle the light path between thetiming mark light source and its associated photo-diode. Shutter 16 willbe actuated, and assuming the character to be photographed is the topmost in the column of characters, a clear path will exist from thecharacter drum through the collimating lenslet 15, the zoom lensassembly 17, the decollimator or imaging lens 23 to mirror 24 and thefilm plane at which the sensitized sheet is placed. Upon decoding thecharacter signal, the width information for the character will beretrieved from the electrical circuitry of the system, and mirror 24will be stepped to a position thereby determined from the characterwidth information and the point size of the image to be recorded on thesensitized sheet. Now the character drum is stepped one position tocause the timing mark associated with the character to be photographedto cross the light path between the timing mark light source andphoto-diode. At the instant the edge 67 of the transparent timing mark,e.g. 65, crosses the light path, the photodiode is energized and thistriggers the main source of illumination 11 which thereupon flashes andprojects the selected character image to the film plane where it isrecorded as a latent image on the sensitized sheet. The next charactercode is decoded and mirror 24 will thereupon be stepped a distancedependent on the width of the character to be photographed so that thenew character will be projected to an unexposed portion of the film orthe sensitized sheet. The drum 10 will be stepped such that the timingmark for the new character to be photographed and the timing markadjacent thereto straddle the light path from the light source tophoto-diode. The shutter 16 will be actuated so that the blade thereofassociated with the selected character or more specifically with itsposition in the already selected column of characters, is actuated toestablish a clear path through the optical system whereupon characterdrum 10 is then given a one position step with the selected characterbeing photographed as the right hand edge 67 of the timing slit crossesthe light path to the timing make photo-diode. It is to be noted thatalthough the character drum is initially stepped to bring the selectedcharacter near the photographic position, the stepping mechanism neednot be of the accuracy normally associated with photocomposing machinessince the position at which the drum stops is not the position at whichphotography takes place. The photographing of the character occurs whenthe drum is in motion, but precisely located in relationship to theinstant at which the light source 11 is flashed, the result being thatthe accuracy in placing the character image on the sensitized sheet orfilm is very high. It might also be noted that the drum need not befully stopped when it is stepped to its initial position just prior tophotographing of the selected character but rather may still be huntingor vibrating to find the rest position. During photographing of a lineof characters, the rotation of the drum from one character selection tothe next is measured from its previous position so that there is no needfor the drum to return to its home position between the photographing ofsuccessive characters. in other words, if the first character selectionrequires the drum to step 10 positions, from its home position the nextcharacter is eight positions from the home position, after the firstcharacter is photographed the drum is stepped two positions back towardsthe home position. It may even be the case that the next selectedcharacter is in the same column as the first selected character so thatthe drum movement would not be required other than to cause the timingmark for that character and the next adjacent timing mark to straddlethe light path from the timing light source to the photodiode afterwhich the drum is given a one step movement to cause photographing ofthe selected character while the drum is moving as previously explained.

At the completion of a line of characters the drum will he stepped toits home position prior to the photographing of a next line. This isdone so that if any error inadvertently occurs in the stepping of thedrum during one line of composition, the error will not be carried overthrough successive lines but rather will be limited to the one line inwhich it occurs. If the point size is to be altered, lens 20 and lens 21will automatically be repositioned in accordance with a code entry onthe control tape so that the photographed characters will be recorded onthe sensitized sheet in a point size determined by the new rrangement ofthe optical elements in the zoom lens assembly. Control of the movementof mirror 24 to accord with the new point size will be determined by theelectrical circuitry. In the event that large point sizes are to bephotographed in the film plane 30 rather than in film plane 25; mirror24 will be repositioned to the position shown in dotted line in FIG. 1.In this case the optical path will be traced through zoom lens assembly17, the decollimator lens 23, mirror 24, auxiliary lens 26, andpentaprism 27 to the film plane 30. Since this optical path is used onlywhen setting display or headline characters, the film will be tranportedafter each character is imaged thereon. This can be done automaticallyby a film transport mechanism that responds to the width of thephotographed character which will in this case be stored in theelectrical circuitry of the photocomposing machine or the film can betransported manually by a machine operator who can advance the film bymeans of a simple crank mechanism.

Having thus described my invention it should be obvious that manyapparently widely different embodiments of the inventions can be madewithout departing from its spirit and scope. For example, instead ofshutter 16 an individual flash lamp could be located behind eachcharacter image location in the photographic position, so that when acolumn of characters is brought to the photographic position, theselected character is exposed by flashing the appropriate lamp.Therefore, it is intended that the foregoing specification and thedrawing be interpreted as illustrative rather than in a limiting sense.

What is claimed is:

l. A photocomposing machine comprising: a character carrier having afont of typographical characters thereon suitable for imaging onto asensitized medium; means, including a bi-directional stepping motor, forrotating said character carrier to bring a group of characters includingthe one selected for imaging onto the sensitized medium to a firstposition adjacent the imaging position; means, including controls forcausing said stepping motor to move one step in one predetermineddirection, for moving the group of characters through the imagingposition; and means for projecting an image of the selected characterfrom said group of characters to the sensitized medium as the group ofcharacters is moved through the imaging position.

2. A photocomposing machine according to claim 1 wherein said charactercarrier is in the form of a drum and wherein the character images onsaid character drum are arranged in column and rows, and wherein a groupof characters brought into position to be photographed are thosecharacters in a column of characters.

3. A photocomposing machine according to claim 2 wherein said characterdrum comprises a transparent drum and a flexible font element mountedthereon, and

including means for mounting said font element on said drum.

4. A photocomposing machine according to claim 3 wherein said mountingmeans include a pair of hooklike members for grasing one end of saidfont element, and a pair of retaining members for securing the other endof said font element on the periphery of said drum.

5. A photocomposing machine according to claim 4 including a pair ofalignment pins on the periphery of said drum.

6. A photocomposing machine according to claim 7 including means fortransporting the second sensitized film after each character is imagedthereon so that successively imaged characters are located in side byside relationship.

7. A photocomposing machine according to claim 1 wherein said imageprojecting means includes a mirror means that is pivotted in step wisefashion to put successive character images in side by side relationshipon the sensitized medium, and including means for moving said mirrormeans to a predetermined fixed position from which images of selectedcharacters are directed towards a senitized film strip, and auxiliaryoptical means located between said mirror means and the sensitized filmstrip.

8. A font element for use in a photocomposing machine having a rotatablecharacter drum, said font comprising a flexible photographic negative onwhich character images are arranged in rows and columns, a plurality oftiming marks arranged along one edge of said negative, one timing markfor each column of character images, a plurality of apertures in saidnegative whereby said negative is attached to the character drum, areenforcing member secured to one end of said photogrphic negative, asecond reenforcing member secured to the other end of said negative,wherein the plurality of apertures in said negative include twoapertures adjacent to said other end of said negative and spaced apartfrom each other, and wherein said second reenforcing member is securedto said negative between said two apertures, and two spring means eachprojecting from an end of said second reenforcing member, each springmeans traversing one of said two apertures.

UNITED STATES PATENT AND TRADEMARK OFFICE CTIFICATE OF CORRECTION PATENTNO. 3 73 23 DATED 2 June 12, 1973 INVENTOR(S) 3 Wolfgang Otto Grube,Joel S. rHarris, Uri Z. Escoli It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1 line 10, after "fashion" insert in--; line 13, for "cahracters"read -characters--, and for "dfferent" read -different--; line 23, for"btween" read --between; line 27, for "front" read --font--; and line49, for "slected" read -selected-. Column 2, line 4, for "dscription"read description; line 18, delete "rotary mounted for"; and line 39, for"solenid" read -soleniod-. Column 3 line 17,

for "energes" read-emerges-; and line 28, for "controled" read--controlled-. Column 4, line 18, for "chracters" read characters; andline 48, for "reenforcng read --reenforcing--. Column 5, line 31, after"position" insert --that; line 33, for "firct" read --first. Column 6,line 58, for "rrangement" read -arrangement-.

Column 8, line 5 for "grasing" read grasping; line 27, after "font"insert --element--; and line 35, for "photogrphic" read -photographic-.

Signed and Scaled this .tSEAL] ninth D3) of December 1975 Attest:

RUTH C. MASON C. MAR H Arrestin 0m 3 ALL DAN Commissioner uj'Parenrs andTrademarks PATENT 3, 738, 236

DATED June 12, 1973 INV ENTOR(S) Wolfgang Otto Grube, Joel S. :Harris,Uri Z. Escoli It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 10, after "fashion" insert in-; line 13, for "cahracters"read --characters, and for 'dfferent" read different-; line 23, for"btween" read --between; line 27, for "front" read -font-; and line 49,for "elected" read -selected--=. Column 2, line 4, for "dscription" read-description-=-; line 18, delete "rotary mounted for" 7 and line 39, for"solenid" read -soleniod-. Column 3, line 17, for "energes"read--emerges-; and line 28, for "controled" read ---controlled--.Column 4, line 18, for "chracters" read characters--; and line 48, for"reenforcng read -reenforcing-., Column 5, line 31, after "position"insert -that---; line 33, for "firct read -first-. Column 6, line 58,for "rrangement" read -arrangement-.

Column 8, line 5, for "grasing" read -grasping; line 27, after "font"insert element-; and line 35, for "photogrphic" read --photographic-.

Signed and Scaled this A ttest:

RUTH C. MASON C. MARSH lesring Officer mnmissioner uj'Patenrs andTrademarks

1. A photocomposing machine comprising: a character carrier having afont of typographical characters thereon suitable for imaging onto asensitized medium; means, including a bidirectional stepping motor, forrotating said character carrier to bring a group of characters includingthe one selected for imaging onto the sensitized medium to a firstposition adjacent the imaging position; means, including controls forcausing said stepping motor to move one step in one predetermineddirection, for moving the group of characters through the imagingposition; and means for projecting an image of the selected characterfrom said group of characters to the sensitized medium as the group ofcharacters is moved through the imaging position.
 2. A photocomposingmachine according to claim 1 wherein said character carrier is in theform of a drum and wherein the character images on said character drumare arranged in column and rows, and wherein a group of charactersbrought into position to be photographed are those characters in acolumn of characters.
 3. A photocomposing machine according to claim 2wherein said character drum comprises a transparent drum and a flexiblefont element mounted thereon, and including means for mounting said fontelement on said drum.
 4. A photocomposing machine according to claim 3wherein said mounting means include a pair of hook-like members forgrasing one end of said font element, and a pair of retaining membersfor securing the other end of said font element on the periphery of saiddrum.
 5. A photocomposing machine according to claim 4 including a pairof alignment pins on the periphery of said drum.
 6. A photocomposingmachine according to claim 7 including means for transporting the secondsensitized film after each character is imaged thereon so thatsuccessively imaged characters are located in side by side relationship.7. A photocomposing machine according to claim 1 wherein said imageprojecting means includes a mirror means that is pivotted in step wisefashion to put successive character images in side by side relationshipon the sensitized medium, and including means for moving said mirrormeans to a predetermined fixed position from which images of selectedcharacters are directed towards a senitized film strip, and auxiliaryoptical means located between said mirror means and the sensitized filmstrip.
 8. A font element for use in a photocomposing machine having arotatable character drum, said font comprising a flexible photographicnegative on which character images are arranged in rows and columns, aplurality of timing marks arranged along one edge of said negative, onetiming mark for each column of character images, a plurality ofapertures in said negative whereby said negative is attached to thecharacter drum, a reenforcing member secured to one end of saidphotogrphic negative, a second reenforcing member secured to the otherend of said negative, wherein the plurality of apertures in saidnegative include two apertures adjacent to said other end of saidnegative and spaced apart from each other, and wherein said secondreenforcing member is secured to said negative between said twoapertures, and two spring means each projecting from an end of saidsecond reenforcing member, each spring means traversing one of said twoapertures.